1. Field of the Invention
This invention relates to systems and methods for scanning a sample tray with a plurality of samples. The invention further relates to detection systems for detecting fluorescence from a plurality of samples in a sample tray.
2. Background
Biological testing involving analyzing the chemical composition of nucleic acid samples in order to determine the nucleotide sequence of the sample has become increasingly popular. Currently, experiments in chemistry and biology typically involve evaluating large numbers of samples using techniques such as detection of fluorescence emitted from a sample in conjunction with a polymerase chain reaction (PCR). These experiments, as well as other techniques such as sequencing of nucleic acid samples, are typically time consuming and labor intensive. Therefore, it is desirable that a large number of samples can be analyzed quickly and accurately. With large scale projects such as the Human Genome Project, it is desirable to increase throughput of nucleic acid sequencing and polymerase chain reactions.
Existing systems are typically not well-adapted for real-time detection of a plurality of samples in an efficient manner. Existing systems typically include a separate detector for each sample well and are not compatible for large-scale testing using fluorescent detection. Therefore, there is a need for an efficient method and system for real-time detection of a plurality of sample wells of a sample well tray.
The advantages and purposes of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages and purposes of the invention will be realized and attained by the elements and combinations particularly pointed out in the appended claims.
To attain the advantages and in accordance with the purposes of the invention, as embodied and broadly described herein, the invention includes a scanning system for detecting fluorescence emitted from a plurality of samples in a sample tray. According to certain embodiments of the invention, the optical system generally includes a plurality of lenses positioned in a linear arrangement, an excitation light source for generating an excitation light, an excitation light direction mechanism for directing the excitation light to a single lens of the plurality of lenses at a time so that a single sample holder aligned with the lens is illuminated at a time, and an optical detection system for analyzing light from the sample holders. The plurality of lenses and sample tray are configured so that relative motion may be imparted between the plurality of lenses and the sample well tray so that the plurality of lenses may linearly translate in a second direction perpendicular to a first direction of the linear row of sample holders. Preferably, the excitation light source directs the excitation light to each of the sample holders of a row of sample holders in a sequential manner as the plurality of lenses linearly translates in the second direction. A sample in the sample holder may generate light, e.g. fluoresce, upon illumination. In certain embodiments, the optical detection system includes a light dispersing element configured to spectrally disperse the light from the sample holder being illuminated, and a lens element configured to receive light from the light dispersing element and direct the light onto a light detection device. In certain embodiments, the sample holders are sample wells.
In another aspect of the present invention, the invention is directed toward a detection system for detecting fluorescence from a plurality of sample holders in a sample tray. In certain embodiments, the detection system includes a single excitation source for generating an excitation light, a lens housing comprising a plurality of lenses positioned in a linear row, each lens configured to direct the excitation light source to an aligned sample holder, and a single detection device for analyzing light from the plurality of sample holders. The linear row of lenses is arranged to be angularly offset relative to an adjacent row of sample holders.
In yet another aspect of the present invention, the invention includes a method of scanning a sample tray having a plurality of samples positioned in sample holders to detect fluorescence. The method includes generating an excitation light with an excitation light source, directing the excitation light to a first lens of a row of lenses, the row of lenses being angularly offset relative to an adjacent row of sample holders, illuminating a sample in a first sample holder of the row of sample holders positioned adjacent the row of lenses with the excitation light to generate an emission light, optically detecting the optical characteristics of the emission light, directing the excitation light to a second lens positioned adjacent the first lens of the row of lenses, illuminating a sample in a second sample holder of the row of sample holders to generate an emission light, and optically detecting the optical characteristics of the emission light from the second sample holder. Throughout the above method of scanning, relative motion is imparted between the row of lenses and the sample tray so that the row of lenses is linearly translated in a direction perpendicular to the row of sample wells.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.